Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

245
FXUS63 KLOT 241937
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
237 PM CDT Fri Apr 24 2026

.KEY MESSAGES...

- Seasonable and dry conditions over the weekend, but colder
  near the Lake Michigan shore.

- Severe thunderstorms Monday along with heavy rain and
  possible localized flooding.

&&

.DISCUSSION...
Issued at 237 PM CDT Fri Apr 24 2026

Stratiform rain associated with a passing mid-level wave is now
confined almost exclusively east of I-57, and will gradually
end from west to east through the afternoon. Thunderstorm
potential remains quite low, with the only focus in the far
southeast CWA where cloud tops may become barely sufficient for
a lightning strike late this afternoon. Farther west, a cold
front entering the western CWA will track across the remainder
of the area through mid-evening. Abundant cloud cover and slight
low-level dry air advection has limited cumulus growth and will
likely prevent new precip generation during the remainder of
the day.

High pressure drifting eastward across the northern Great Lakes
this weekend will promote dry and mostly clear conditions.
Temps will be seasonable to seasonably warm well inland.
Persistent east to northeast winds will lead to substantially
cooler conditions with high in the upper 40s Saturday and mid
50s Sunday along the Lake Michigan shore. Cannot rule out some
lake-induced fog or low stratus along the shore each morning as
well.

Focus then turns to a potential severe weather event over and
west of the area on Monday as deep troughing ejects
northeastward over the central Great Plains. Impressive mid and
upper-level dynamics shifting between the MO/MS River valleys
Monday afternoon should quickly erode a modestly strong cap and
force discrete convection around the I-35 corridor. Convection
would likely congeal with eastward extend across the MS River,
favoring primarily a QLCS set-up over some or all of our area
late Monday afternoon and especially Monday evening. The
intensity of convection with eastward extent, however, remains
somewhat in question due to 1) the ability for less- pronounced
forcing farther east to erode the cap and 2) amount of low-level
moisture advection as flow remains backed and nearly parallel
to a notable moisture gradient. Obviously we are still a few
days out to hone in on more details, but conditional on a more
favorable thermodynamic farther east, discrete supercells with
all severe hazards are a possibility over or particularly south
and west of the forecast area, followed by a damaging wind
threat with embedded QLCS tornadoes. Will also need to monitor
for a flooding threat, especially north of I-88 where river
flooding is ongoing, if convection becomes more widespread
and/or slower moving.

Behind Monday`s system, a transition to longwave troughing over
the eastern Great Lakes and eastern Ontario/Quebec will favor a
cooler (still seasonable) end to April with perhaps a couple
chances for showers later in the week.

Kluber

&&

.AVIATION /18Z TAFS THROUGH 00Z SUNDAY/...
Issued at 1224 PM CDT Fri Apr 24 2026

Key messages:

- A few showers possible at the eastern terminals this
  afternoon.

- West-northwest winds this afternoon shift north-
  northeasterly late this evening and overnight.

- Potential (20-30% chance) for a period of IFR to low MVFR CIGS
  late tonight through around daybreak Saturday morning.

Some patchy areas of MVFR CIGs continue to shift across the
area early this afternoon in advance of a cold front shifting
into the area. These are expected to be short lived early this
afternoon, with generally VFR conditions anticipated this
afternoon and evening. Otherwise, there is an area of rain
currently working its way northeastward across east central IL
into northwestern IN in advance of this front early this
afternoon. While a few of these showers may make shift across
the eastern terminals for a period this afternoon, their
duration is expected to remain rather short.

West-northwesterly winds setting up in the wake of the cold
frontal boundary this afternoon will shift north-northeasterly
late this evening and overnight. This may promote some IFR CIGs
developing inland off the lake across portions of northeastern
IL and northwestern IN for a period overnight. However, due to
low confidence on the extent of IFR CIGs, we continue to only
mention a scattered deck around 600 feet. Any low clouds that
move in off the lake should improve by mid morning on Saturday.
Accordingly, VFR conditions are expected during the day
Saturday, with breezy east-northeasterly winds.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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